The CAS Registry Mumber 76143-39-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,1,4 and 3 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 76143-39: (7*7)+(6*6)+(5*1)+(4*4)+(3*3)+(2*3)+(1*9)=130 130 % 10 = 0 So 76143-39-0 is a valid CAS Registry Number.